Smart TV is a television set with internet capabilities, computing ability, and broadcasting service that increases user interactions. Usability has been regarded as one of the most important criteria for measuring and evaluating smart TV. To evaluate smart TV from the perspective of usability, we first need to develop a measurement model by determining the major factors affecting usability, which become a measurement the evaluation criteria of the model. The objective of this paper is to suggest an AHP(Analytic Hierarchy Process) model for measuring usability of smart TV. Factors affecting usability are described from the prior research. We show how the judgment data is acquired and the usability score is computed by an numerical example.